Control apparatus



"W. H. SMITH. CONTROL APPARATUS.

APPLICAT ON FILED JULY 19,1917,

Patented Sept. 14, 1920.

8 SHEETS-SHEET I- INVENTOR 14 1/72? /7. J/m'f/J WETNESSES: M

ATTORNEY W. H. SMITH. CONTROLAPPARATUS. APPLICATSON FILED JULY 19,1911.

1,352,483, PatentedSe'pt. 14, 192 0.

8 SHEETSSHEET 2.

W ITNESSES: I INVENTOR 6? W 1mg mm ATTORNEY 'W. H. SMITH.

CONTROL APPARATUS;

APPLICATION FlLED JULY 19,1917.

1 52,483, Patented Sept. 14, 1920,.

8 SHEETS-SHEET 3-.

fGMu/Id I WiTNESSES: INVENTOR Wa/ferH 507/797.

MM v AT'ILORNEY W. H. SMITH.

CONTROL APPARATUS.

APPLICATION FILED JULY 19,1917.

1 352,483 Patented Sept. 14, 1920.

BSHEETS-SHEET 4.

A 45 2 A ATTORNEY W. H. SMITH.

CONTROLAPPARATUS.

APPLICAT ON FILED JULY 19, 19]].

WITNESSES i aoented Sept. 14, 1920..

8 SHEETSSHEET 5- INVENTOR 7 ATTbRNEY W. H. SMITH.

CONTROL APPARATUS.

APPLICAHON FILED JULY I9, I917.

1 852,483 Patented Sept. 14, 1920.

8 SHEETS-SHEET 6. 35%

w. H. SMITH.

CONTROL APPARATUS.

APPLICATION FILED JULY 19, I917- 1,352,483. PatentedSept 14,1920.

8 SHEETS-SHEET 7.

WITNESSES: v lZ/ E RZL a 17 d, 3/ /77/ BY QM/L/ ATTORN EY H. SMITH.

CONTROL APPARATUS.

APPLICATION FILED JULY I9, IUIZ.

AiTORNEY UNITED STATES PATENT OFFICE.

WALTER H. SMITH, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WES'lI] TG1-I0USE ELECTRIC.& MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CONTROL APPARATUS.

T 0 aZZ whom it may concern Be it known that I, i i nnrnn H. SMITH, a citizen of the United States, and a resident of 1V ilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Apparatus, of which the following is a specification.

My invention relates to control apparatus and especially to pneumatic control systems for governing electric railway motors and the like.

The object of my invention, viewed in its broadest aspect, is to provide a control system. for electric motors which shall be almost entirely fiuid-pressure-operated and governed, whereby practically all electric circuits are eliminated, thus producing a system that is less expensive to manufacture and maintain in operation than the present all-electric or electro-pneumatic control systems. v

More specifically stated, it is one object of my invention to provide an all-pneumatic multiple-unit control system which shall be capable of effecting automatic control of one or more dynamo-electric machines in a manner analogous to that now provided by allelectric or electro-pneumatic control systems and which embodies regulating and safety features corresponding to those of the prior art, such as are employed in the familiar types of electric railway vehicles.

Viewed from another angle, it is an object of my invention to provide a fluid-pressureoperated control system, primarily governed by manually actuated pneumatic means, together with pneumatic regulating devices that are actuated in accordance with the current traversing the governed machines,

whereby the automatic operation of the systiall in section and partially in elevation,

of the general layout of a pneumatic con:

1917. Serial No. 181,523.

trol system constructed and arranged in accordance with the invention; Fig. 2 to Fig. 9, inclusive, are detail views serving to more completely illustrate various pieces of control apparatus that are shown in Fig. 1; Fig. 10 is a view, in side elevation, of a group of pipes or conduits corresponding to the familiar train-line conductors of the electrical or elcctro-pneumatic control systems; Fig. 11 is a diagrammatic view of the main circuits of an electricmotor system that is governed by my present auxiliary control system; Fig. 12 and Fig. 13 are. developed views and Fig. 1 1, Fig. 15 and Fig. 16 are elevational views, of an auxiliary appliance that may be substituted for one of the pieces of control apparatus that is illustrated in Fig. 1; Fig. 17 is a semi-diagrammatic view of a modified form of the general apparatus layout, corresponding to Fig. 1; and Fig. 18 is a sectional view of a modification of one of the pieces of apparatus that are shown in Fi 17.

eferring to Fig. 1 of the drawings, the pneumatic system shown comprises a fluidpressure operated controller actuating mechanism 1; a primary governing means or manual control valve '2 corresponding to the familiar master controller of electrical systems; an automatic operating valve 3; an electro-pneumatic limit valve 1-; an electro-pneumatic overload trip that pneu matically communicates with the controlleractuating mechanism 1 for governing purposes to be set forth; and a fluid-pressure operated controller-shifting apparatus 6.

The controller-actuating mechanism 1 comprises a pinion 9 which is rigidly secured to the circuit-governing member or operating shaft 10 of the main-circuit controller and which meshes with a reciprocatory rack member 12, the opposite ends of which constitute pistons 13 and that travel within suitable operating cylin ers 15 and 16, respectively. A pipe or corn 17 effects communication between the cylinder 15 and the electro-pneumatic (6110311 trip 5, while a plurality of pipes or conduits 18, 19 and 20 pierce the walls of the cylinder 16 at predetermined points and respec tively communicate with the automatic o erating valve 3, the electro-pneuriatic i it valve 1, and with a second similar limit valve (not shown).

Specification of Letters Patent. Patented sjapt. 14, 192i).

The mechanical Operation of the controller-actuating mechanism 1' may be set forth initially biased to the illustrated position.

as follows; Norn1ally5 as subsequently traced in. detail, fiu1d' pressure is adm1tted to the cylinder 16 but is excluded from the cylinder 15, which communicates with the atmosphere. Consequently, the

Upon the reversal of such initial conditions that 1531110011 the release'of fluid from the cylinder 16 and the admiss'lonof fluid pressure to the cylinder 15, a down wardmovement of the pistons, as viewed in E1 1 1S reduced to effect a counter-clockwise rotative movement or the controller shaft viewed from the 1l 'l1tof theli ure.

7 To arrest such movement at any time it is vmerely necessary tore-admit flu1d.'pres'sure to the cylinder 16, whereupon v balanced 'high-fiuid-pressure conditions obtain in the mechanism and" a positive and reliable stoppage thereof iseffected. To produce a back ward-movement of the mechanism,- fluid pressure conditions are caused to revert to the original unbalanced state, 7 whereby the desired returnrmovement toward the illustrated normal position is broughtabout. 7

Referring also to Fi 2 and'Fig. .3, the manual controlvalve 2 comprises a centrally-located shaft 25 upon which is loosely mounted a notching plate 26 that is provided'with a set of peripheral teethor projections 27 and a set of lateralteeth 28,

each set respectively corresponding to open; 'ative positions a and b of the valve. plurality of L A orts or apertures 29, 3 0 and 31 a re zprov'eed, selected points in the plate 26; for governing purposes to be de scribed. Furthermore, a'recess or depression 32 in the under-side of the plate 26 is 1 provided for a similar purpose. A plurality of pipes orconduits 21, 3e and '35, respectively effect communication be tween the manual control valve 2 and a second automatic: operating "valve (notshown) that is similar to the automaticv'alve 3, thejelectropneumatic overload trip 5,. the reservoir or source of fluid pressure valve 3. y

In the illustrated off position of the manual control'valve 2, the pipe 33 regis- (not shown), and the automatic operating tem with the port 29, whileports 30 and 31 are respectively located to'register with" pipes35 and 21 in the control valve. v V

The valve structure further comprises a positions a and 5 of stationary base or mounting plate 40; an

upper incasing member or shell 41;a han dle' member 12 and a helical spring as which operates between the shaft 2 5 and V the notched plate 26 for the purpose of re turning the control valve to the illustrated ofi position whenever pressure from the morefully set forth. h I u I Y The handle member l2is shown as compp atus is V,

and, the other-end of which 1s apertured to ressure train operators hand is released from the handle member 42, thereby providing a deadanaifs release feature, as hereina fter prising a body or bar'50, one endof which is; detachably secured to the valve-shaft 25 receive-a pin 51 towhich is attached the customary wooden grip 52. The lower end of the pin 51 rests upon the horizontal arm of a bell-crank lever 53 which is pivoted upon a projection of the bar '50 at an intermediate point 54, the vertical arm of the bell-crank lever abutting against a link member 55 which is intermediately pivoted at 56 upon aprojection 50 of the bar 50-. The link 55 hasfa pin-and-slot' connection 57 with a lower sli dable" rod 58 and a pivotal connection '59 with an upper slidable rod 60; both rods extending through downately pivoted at 64 upon the shell 4-1 of the valve and is provided with a dependent tongue 65 that is'mounted upon a pivot 66 to operate within a 'grooveof thevshell being biased downwardly to engage the lat-V eral teeth 28 of'the notched plate 26, by means of a fiat spring 6? which is fastened to the shelled. 7

Assuming that the manual control valve occupies theposition illustrated in Fig. '2, a downward pressure from the train-operators hand upon the grip 52 effects co'r responding or clockwise movement of the horizontal 'arm of the bell-crank'lever thereby causing a" clockwise-movement of' the link 55 around its inter 'mediate pivotal point 56'and thus pro ducing a movement of the lower slidable rod 58 toward the left and of the upper slidable rod '80 toward the right.

' The lower rod 58 may thus engage the first peripheral tooth 27 (corresponding to positlon a) of the notch-111g plate 26, and a subsequent rotativei movement of the actu atinghandle in the counter-clockwise direct1on, as viewed 1n Fig. 1 or Fig; 3, pro-e against the vertical arm 68 of right-V angled lever member wh1ch 1s, intermedi duces a movement of the control valve 2 into its initial operative position a, where the valve may be maintained stationary as long asthe downwardp-ressure on the grip 52 obtains, by reason of the above mentioned longitudinal movement of" the upper rod 60, which permits the flat 67 to downwardly actuate the tongue into locking engagement with the first lateral tooth 2-8 of the plate 26. 7'

Thus, the lower slidaiole rod 58 and the peripheral teeth ,2? effect step-by-step movement of the manual control valve 2, the lateral teeth 28 and the interlocking mechanism that is associated with the upper slidable rod 60 serving to hold the valve in each position and permit further forward operation of the valve while 'dowre ward pressure from tl e operators hand is maintaine l.

lVhenever pressure upon the handle grip 52 is released by reason of incapacitatien of the train operator, or otherwise, the predominating spring 62 ret irns the linkage mechanism to the position illustrated in Fig. 2, thereby allowing the heli al spring 43 to immediately return the notched plate 26 and the handle member 42 to the nor- 7 mal or oil position. It will be understood that other forms of dead-mans release mechanism may be employed in lieu of that just described or if desired, the manual control valve may be constructed in a simple manner which merely provides a step-by step movement in either direction upon ro tation of the actuating handle.

For the purpose of reversing the e i cal relations of the armature and held windings of the motors to be governeth the familiar fluid-pressure-operated device, embodying a pair of mechanically-connected pistons that operate within a cyriur er and are actuated in the one or the other tion, dependent'upon the admission oi fluid pressure to the corJesponding end oi" tl cylinder, is preferably provided. P ince tl device just outlined is thorou hly familiar dir to those skilled in the art and, turtl ermere, generically resembles the controller ac uating mechanism 1, no further illustration or description thereof is believed to be n'eces sary.

To control the above-mentioned admission of fluid pressure to the moter-reverser device, a manual auxiliary rerersing apparatus may be conveniently associated with the manual rontrol valve 2, as illustrated in Fig. 3. The auxiliary re'xerser is shown as comprisi g a semi-cylindrical incasing member 71 that may be integp'ally or otherwise, related to the shell "ti 0:; the valve 2, and an operating shaft having a rectangular head T2 that is inclcsed on 5 sides but one by a collar 72% wiereby o erative access to the shalt head 72 may be obtained only when the manual reversing valve occupies the illustratedintermediate or off position.

l'he of the tee tc gassag e e Quillmunica :2. IQSBI'VOlT'fiOIlIlGClLQCL pipe i l and an out et pipe 1e is actuated -ytlie i handle position that is indicted by d i th le Eerward mittcd to the verser to et'fe connections,

nan

teunednzte i V L i J mu J 1 Lu 'i and lar 1 tuati I be 1 pers s c only when i l eccu trated oli posi' p "he actu:

in the (c- 114 ill roro s act tic ant e e 1 u t its operative positions.

5* w 1. 1. t ,i r urthermoie, the ioca s i r i it head Y2 are ma 1 the sh the manual re "X515 4) o is l the annual cent sition, i

between such the de 1 trol a; L.

.uton' atic operat' a duplex structure hari ent suitably cluiniliered val *e not 8 that l side-,1 y-side 7 l 9l'1 with a ioubl valve 2i. whica 15 nor: by a ;c the ilh lira wher Lal n elly-prot pper end it 11.5

chambered pc "d nal end of which is pivotally associated Thus a downward movement of the clue 7 L Q valve member 22 produces an upward movementot the plug valve member 2 1, and vice versa. 7 1

V The electro pneumaticlimit valve 1, shown completely in Fig. 4, comprises a chambered cylinder or shellSO having a plug valve member 81; that normal permits. communication between the pipe-19 and pipe 82 which leads to the automatic operating valve 3 and which, in its upper position, shuts oft communication between those pipes. A horizontally-e1tending oscillate ble arm 83 has one end pivoted within the shell 80 at the point and a right-angled link 85is pivotally secured to the outer end of the arm83 ext-e all the upper end of the link being attaches to a spindle 86 which is vertically movable within a bracket member 8? and is supported by the upper surface 0 the shell A suitable magnetizable core 88 is mounted upon the spindlefio and is adapted to be actuated to its upper position whenan inclosing coil 89, which is connected in the main-motor circuit as diagrammatically illustrated in 11, is energized above a predetermined amount, whereby the link 85 and the arm 83 are likewise raised to effect actuation of the plug valve member 81 to its upper position; The valve thus performs a function similar to that of the well limit switch in electrical systems, fully described later.

Referring to Fig. 5, the electro-pneumatic over-load trip 5 comprises a duplex body member having independent suitably chambered portions and 96 that are located side-by-side, the pipes 1'7 and communicating with the portion 96 and the pipe 34 and a further pipe 97, which leads to the controller-shifting apparatus 6, communicating with the valve portion 95.

A double-ended plugvalve 98 is biased by V a helical spring 99 to the illustrated position within the valve portion 95, whereby access of fluid pressure from the supply pipe 3 1 to an aperture or passage 100 is cut off, while communication between the pipe 97 and an outlet port 101 through an internal passage 102 is permitted. A downwardlyextending pin 103 is integrally, or otherwise, secured to the plug valve member 98 to permit actuation thereof by an external agency, as subsequently set'torth. Y

The valve portion 96 is similarly provided with a double-ended plug valve member 10 which is biased by a coil spring 105 to the illustrated position, thereby efiecting communication the pipes through an internal passage 106 an nor ially'to the shell ow governed,

;rod 109, the lower end of which is insul stantiallyhorizontal alinement withtha-t of the pin 103. r

A slidable rod 110 has its; upper end located in a centrally situated slot or recess 111 of'tlie Valve body and 1s pi'ovicled, near its upper-end, with a-transverse bar or plate 112 for the purpose of striking the pins 103 and 109 when raised to its uppermost pOsition. The bar or plate 112 preferablyrests upon a coilspring 113 that surrounds the rod 110, thereby providing a cushioning effect when the bar strikes the pins,- 1 The lower portion of the rod 110 has mounted upon it a suitable magnetizable core 114 which, in turn, is inclosed by an cuit with the main motor or motors-to be p as diagrammaticallyshown' in 11. A magnetic keeper or armature 116 tion, where it is held by meansrot' a latch actuating" coil that'is connected in cir- 90 has'one end pivoted at 117 and, upon'a pre-, "ermined energization of the magnetizablecore 114 by the coil 115, the armature 1 16 is raised to a substantially horizontal posi- 118, of a familiar type, which is intermediately pivoted at 119 and is biased to alatching position'by asuitable spring 120. Consequently, upon the occurrence eta predetermined overload current in the motor circuit, the core 114; is raised into such a position that the'trans'verse bar'112. strikes the pins 103 and 109 and raises the plug valves 93 and 10% into their upperpositions, where they are maintained by reason of the latching mechanism. To permit further opera tion of the system, the latch 118 may be' manually, or otherwise, actuated to allow the armature 116 to drop to an inoperative position, whereby the overload trip is reset in readiness for the next operation, in ac cordance with a familiar practice.

The controller-shiftin apparatus 6 comprises a cylinder-and-piston device or other pneumatic engine a double-diameter cam member 126 and a resetting cam device 127, with both of which an oscillatable memher or arm 128 is associated as hereinafter to be set forth; and a valve member 129 for governing the operation of theshitting apparatus under predetermined conditions.

The pneumatic engine 125 is shown in sec tion in Fig. 1 andcomprises a cylinder or 'in-' casing member 131 within which travels apiston 132 that is'biased to one extreme posit on by means of a coil spring 133. The pi, ton stem 134 constitutes an ntegral or otherwise operatively-related extension of the controller shit 10, whereby a longitudinal. movement's-1? the piston 132 v o troller shaft 10 a distance su'iiicient to quickly break contact between all of the active stationary and movable contact 1nembers of the eontrolle', as subsequently explained. In this way, the motor circuits may be rapidly interrupted under predetermined conditions and, in particular, the controller may be returned to its initial position without requiring the opening of circuits in the reverse sequence to that employed during forward rotation. In this 1 manner, undue wear and pitting and burning of contact members are obviated.

The cam member 126 comprises a portion 135 of relatively great diameter that corresponds to, and is employed during, tlr ward movement of the controller sisecond cam surface 136, of materially diameter, corresponds to, and is utilized curing, forward or operative movement of the controller shaft. A roller 13?, or other suitable friction-reducing device, is employe-ll for effecting engagement of the cam member 126 with the oscillatable arm 128.

The surface of the smaller-diameter cam portion 136 is substantially cylindrical, while the surface of the larger diameter portion 135 is' cylindrical, for the most part, and is provided with a recess or depression 138 of V a size corresponding to the roller 137, this recess normally housing the roller when the cam member 126 and the controller occupy the illustrated off position. The larger cam portion 135 is also provided wi h a tapered recess 139 of such a shape that the,

roller 137 will be quickly forced from the depression 138 to the small cam surface 136 upon a slight forward or clockwise movement of the controller, and the roller 137 rests upon the smaller cam surface 136 throughout subsequent forward operation. One or more lateral notches 135 are provided to lift the roller 13'? from the smaller-diameter to the larger-diameter cam surface upon backward controller movement.

The roller 137 is mounted upon a bolt or rod 110 which extends between spaced lugs 11-1 and 142 of the body portion 1&3 forming part of the osoillatabie arm 128. The end f thv body portion 143 that is remote from roller 13-7 is pivotally mounted upon a 'ationt standard or bracket 1 15. A coil pring 116, surroundi lg the bolt 1&0, serves t bias the roller 13? toward the right, as viewed in Fig. 6, into the recess 138.

The resetting cam device 127 comprises a bar or rod 150 which is intermediately pivoted t 151 upon a projection 152 o; the air-cyl- 131, for example, and in the upper posi- 1 f the oseillatable arm 128, the rod 150 s adapted to engage a notch 153 of the lug and thereby maintain the oscillatable .rm 1'28 in its upper positionto permit the ion of fluid pressure to the pneumatic engine 125 and thereby produce the previously-mentioned longitudinal shift of the controller shaft 10.

The lower end d 01 the rod 150 is adaptczl to engage a suitably configured cam surface or block 155 that is mounted upon the piston stem 13% just before the controller reaches its off position during returning movement, whereby the rod 150 is unlatched from the lug 14s to allow the oscillatable arm 128 to drop to its illustrated lower position.

he valve device 129 comprises a shell 160 with which communicates a supply pipe 161 1 outlet pipe 162 that leads into the 1 A. doubleended plug valve meme is norma ly biased by a coil spring 6% to the illus ed position, whereby the admission of fluid pressure to the outlet pipe 162 is prevented and the pipe 162 is placed in communication with the atmosphere through an outlet port 165 of the valve.

A pin or rod 166, constituting an extension of the plug valve member 163, projects through the shell 160 and is fastened to the upper end of a heli al spring 167, the lower end of which is positioned over a suitable boss 168 upon the oscillatable arm 128. In this way, a resilient connect-ion is provided between the arm 128 and the valve 129.

l fhen the controller occupies its off position, the roller 13? rests within the recess 138 of the larger-diameter cam surface 135, a previously mentioned. Upon movement the controller and of the cam member in clockwise direction, as indicated by the i Fig. 8, the roller 13? is forced by he inclined surface 139 to ride along the mailer cam surface 136 until the final forward position is reached.

Upon backward movement of the controller, the roller 13? is actuated upwardly 'e wedging action of the corresponding 135 and rides along the larger diamcam surface 135. The arm 128 is latched ts upper p sition by reason of the en agement of the rod 1 .evice 12? with the notch 153. Such upward ii'ivsment furth r actuates the plug valve member permit the admission of fluid pressure to the pneumatic c1 no 125, therebv producing the desired long idinal shift of the controller shaft 10, as previously described. The roller rides along the larger cam surface 135 until the recess 138 is reached, which occurs at approximately the same time that the resetting cam device 12. is disengaged from the oscillatable arm 128, whereby i re roller 13? is allowed to drop into the recess 138 w e the illustrated off position of the co 'oller is attained.

The electri circuits governed by, and the type of contact members embodied in, the main controller are immaterial to my present invention, but the familiar cam-operated type of control apparatus that is illustrated in Fig. 9 is preferably employed.

The apparatus in question comprises a pnuematic'valve 170 which is actuated'by the cams 11 that are mounted upon the controller shaft 10 to govern the admission'of fluid-pressure to a pneumatic engine 171 which, in turn, effects engagement of a set of stationary and movable contact members 172.

The valve 170 comprises a shell or incasing member 125, within which islocated a double-ended plug valve member 17 6 that is biased to the illustrated position through the agency of a coil spring 177., whereby the admissionof fluid pressure from a supply passage 178 to a distribution passage 179 is normally cut oif, and an outlet port 180 is normallyin communicationwith the distribution passage 1'79. The plug valve member 1. 6 is orovided with'an u wardl extendin pin or rod 81 for the purpose of engaging the controller cam 11, whereby the operat on of the contact members is effected. The pneumatic engine 171 comprises an, operating cylinder 182, within which travels apiston 183 that is biased to its lower position by means of a helical spring 18 1.

Inas'much as the illustrated cooperating stationary and movable contact members are of a well-known type, only a brief description thereof will be necessary. The movable contact member 7185 is of the familiar copper-terminal type and is suitably mounted upon a movable arm 185" which is intermediately pivoted at a point186 and is supported through the agency of a boltj187 cured to theplate188 in a similar and welllocated within an opening in the'top supporting plate lSS. The customary blElSlIlg.

spring 189, for, maintaining the movable Contact member'lS 1n the illustrated pos1- tion, is provided. The stationary contact member 190-is of a similar type and is see known manner. I 7

Referring to Fig. 10, the 'set *of hori zontally-extending pipes 192 correspondto the familiar train-line conductors of electrical systems and are fitted with suitable" couplings between adjacent vehicles, in or der to permit multiple-unit operation there- 7 of, as will be understood. 7 The various pipes or conduitsof Fig; 1 which it is necessary or desirable to interconnect in the several vehicles are represented by the sets of vertical pipes 193; which are numbered to correspondto Fig. 7 s In F 1g. 11, a series-parallel control system 10f 'a familiar type,.to which my'present invention. may readily ,be applied is illustrated in a simplified manner; The system comprises supply circuit condnctors Trolley and Ground; a plurality of dynamo-electric -maohii1es respectively having commutatortype ai-matures Al and A2 and field windings F1 and E2 of the series type; variable resistors R1, R2 and R3; the actuating coils 115 and 89 of'the electro-pneumatic overplate 26..

the controller-actuating mechanism 1.,

load trip and the electro-pneumatic limit valve, respectively; and a plurality 'of switches of the type shown in Fig. 9, the

cooperating stationary and movable contact members thereof 7 being correspondingly designated in oneinstance. Since the illustrated system is of a familiar type, employing bridging transition from series to parallel relation, and also'since' the particu lar type of electrical system that is employed in conjunction with my present invention is immaterial thereto,no inrther illustration or description of the system is.

deemed to be necessary. Assuming thatthe various parts of the control system occupy the respectivefposi tions that are illustrated in Fig. 1, the general operationof the system ma be set forth as follows: Normally,"fiuid pressure is conveyed from the reservoir through pipe 36, the internal' passage of the right-hand portion 8 of the automatic operating valve 3 and pipe 18. to the operating cylinder of the controller-actuating. mechanism 1'. On the other hand, the outer end of the operating cylinder 15communicates through V pipe 17,'internal passage 104 of theelectro pneumatic overload trip 5 and pipe to the atmosphere through port- 29. Consequently, the controller-actuating mechanism 1 is maintained in the illustrated position by reason of the unbalanced condition of fluid pressure therein whenever the manual 7 control valve 2 occupies its ca position.

Upon actuation of the manual control valve 2 by means of the previously de-' scribed actuating handle,to-position me eor-I responding to series acceleration, the port 29 is removed from .communication vith the pipe "33 which is plac'ed in communication with the supply pipe 3% tllIOllQ'liillG recess 32 111 the under-side of the notched In this way, flint. pressure directly admitted through the'manual control'va lve 2 to the operating cylinder of but i no movement thereof occurs, since the tin pressures are balancedin the two cylinders 15. and 16. r

. Howeveiythe port30 inthe notched plate 26 of the manual control val've 2 registers with the pipe-35 in position a of the whereby the "internal pass of the pistons 13 and 1-l downwardly, as viewed in Fig. 1, is produced by reason of the unbalancing the fluid pressures in the two cyl'oders 15 and 16.

Such unseating or upward movement of the plug valve member 22 effects a simultaneous downward movement or seating of the plug valve member 24: in the valve portion 8, by reason or mechanical interconnection between the valve members, as previously set forth. Thus, the supply of fluid pressure from the reservoir to the op erating cylinder 16 through the pipe 18 is shut to permit the desired movement of the controller-actuating mechanism 1.

Such movement will continue until the piston 1 1 prevents communication or" the lower or active portion of the operating cylinder 16 with the side outlet pipe 19. Under such conditions, the fluid pressure maintaining the plug valve member 22 of the automatic operating valve 3 unseated, is removed to permit the spring 23 to actuate the plug valve members 22 and 24 to the illustrated position, whereupon fluid pressure is again conducted from the reservoir through the right-hand portion 8 of the valve 3 to the operating cylinder 16, and the resultant balancing of fluid pressures in the mechanism effects a positive and reliable stoppage thereof in a position corresponding to the full series operating position of the governed motors.

However, automatic regulation of the controller movement, in accordance with predetermined conditions, in this case the currenttraversing the motors and, therefore, traversing the actuating coil 89 of the electropneumatic limit switch 4, is provided. lVhenever the plug valve member 81 of the limit valve is actuated to its upper or closed position in the manner hereinbefore described, communication between the pipes 19 and 82 is directly interrupted. In this way, fluid pressure is removed from the left-hand portion 7 of the automatic operating valve 3 to permit the previously-described actuation of the plug valve members 22 and 2d by the spring 23 to the illustrated position, thereby readmitting fluid pressure from the reservoir through the pipes 36 and 18 to the operating cylinder 16 and effecting a rapid stoppage of the pistons 13 and 14.

Upon the occurrence of overload conditions, whereby a predetermined current corresponding to the setting of the overload trip 5 traverses the actuating coil 115 thereor", fluid pressure is admitted from the supply pipe as through the internal passage 100 of the left-hand portion 95 of the overload trip as soon as the plug valve member 98 has been raised to its upper. position, in accordance with the previously-described operation of the device, and thence fluid pressure is conveyed through the pipe 97 to the cylinder 1-31 of the pneumatic engine 125. The piston 132 thereof is immediately moved toward the right against the action of the spring 133 to effect the previouslydescribed longitudinal movement or shifting or" the controller shaft 10, whereby the various controller cams 11 are longitudinally disengaged from the actuating pins 181 of thevalve members 170 that control the op eration of the various sets of contact memhere that are illustrated in Fig. 9. Thus, all controller circuits are opened immediately upon the occurrence of an overload current.

The actuation of the right-hand plug valve member 104: of the overload trip 5 cuts off communication between pipes 33 and 17 and connects the outlet port 107 with the pipe 17, whe eby iuid pressur is exhausted from the operating cylinder 15, and since fluid pressure is present in the other operating cylinder 16, a return movement of the mechanism to the illustrated off position cordance with the movements of the electropneumatic limit valve 4 will continue until the outlet pipe 19 from the operating cylinder 16 is covered by the piston 14:, as already explained.

To effect further operation of the control system. such as the parallel-connected acceleration of the governed motors, the manual control valve 2 is actuated to its final operative position 7) in the manner previously described in connection with Fig. 2 and Fig. 3, whereby communication is maintained between the pipes 33 and 34 by the recess 32 in the notched plate 26, but the registration of the outlet port 31 with the pipe 21 is substituted for the previous registration of the outlet pipe 30 with the pipe 35.

In this way, the other set of governing devices, comprising the previously-mentioned second automatic operating valve (not shown) and second electro-pneumatic limit valve (not shown) are rendered operative to control the action of the controlleractuating mechanism 1 in the previously described automatic manner until the opening of the side outlet pipe 20 from the operating cylinder 16 is governed by the piston 1st. This condition corresponds to the end of the piston travel and to full parallel connection of the governed motors that are shown in Fig. 11.

' coil sarin 220 .o ierates between the bod The structure illustrated in Fig. 12 to Fig. 16, inclusive, constitutes modification of the controller-shifting apparatus 6 that operates solely through the mechanical interlocking of parts, th reby obviating'the necessity for a pneumatic engine and a controlling valve. 5 I i The structure shown comprises a threepart or tripleoperating-surface cam member 200 having a 1 substantially cylindrical end portion 201 of relatively small diameter that corresponds to forward movement of the controller; an end portion 202 of irre ular shape and an intermediate portion 203 of relatively greatdiameter, which Pi'CVlClQCl with a plurality of alternatelyoccurring diagonally-extending ridges or projections 209 and grooves or depressions 210. The cam member 200 is rigidly secured I to ashaft or axle 201- which constitutes an extension ofthe controller shaft 10, correspending to the ,structure that is shown in Fig.1.

The apparatus further comprises an engaging or roller-carrying member 205,'which is best shown in Fig. 16, and a main shifting spring arrangement 206. r V lhe roller-carrying member 205 comprises a contact roller 21: which is rotatively moved; transversely to the direction of rotationof the controller shaft and which is mounted upon a spindle that extends through arms'216 and 2110f the body member 218, the roller 21% being biased to its illustrated lower position by a spring '219'that is located between the arins'216 and 217; Asecond member 218 and a stationaryiportion 221 of toe controller irame, the outer end of the body member .218 being provided with a retaining nut whereby the body member 218 is; adapted to slide within the stationary frame member 221 in opposition to the ac-- tion of the spring 220.-

The main shifting spring arrangement 206 comprises a pin or shaft 225 which constitutes afurther extension of the controller shaft 10 and' is design d to slide through an aperture in a second stationarybracket or frameportion 22 A powerful spring 22' is located between the bracket 226 and la collar 228 of the shaft 225 the spring being adapted to normally maintain the controller longitudinal position.

shaft in'the operative or contact-permitting.

Assuming that the various parts of the: structure occupy the illustrated positions 7 corresponding to the off position of the controller theoperation of the controller shifting apparatus may be set forth as follows: Upon forward movement of the controller throu h the a 'enc of the actuatin mechanism 1 in the 'ClllGCtlOIilIlCllCittBCl by the various arrows, the roller 21 1 is forced bottom surface of the corresponding out of the initial groove 210 corresponding to the off position, as most clearly shown in the developed view, F 1g. 12, into sliding end-surface engagement withthe small-db ameter cylindrical portion 201 .of the cam member 200. No longitudinal movement of the cam member or controller shaft is effected thereby; since the spring 220 is of materially smaller strength than the main spring 227. The roller 21% slides along the cam surface 201 until the next groove or depression 210, corresponding to the first operative position a of the controller, is reached,

whereupon the. roller is retracted by the However, upon backward movement of the controller from any position, the roller 21 i rides along the wedge-shaped surface "of' the corresponding ridge or projection209 and is thus. forced to a position'of engage which, for the most part, has a diameter smaller than that of the bottom surfaceof the grooves 210; and contact of'the' roller with the cam portion 202 15 thus effected byf the downward biasing action of the vertical SPIHLO" 219. i The collar or shoulder 228 upon the shaftex'tension' 225-is positioned tobe engaged by the nut 222 after a slight retractive movement thereof toward the left has occurred. Consequently, the further afc: tion of the cam ridges 209, instead of compressing the spring 220, causes a longitudinal shift of the 'cam member 200 and, therefore of the contfollershaft 10, toward the right, since the spring 227 is sufliciently powerful to prevent compression thereof by In this the wedging action just described. way, the desired longitud nal movement of the controller shaft to open up the various ment with the other end cam portion 202" sets of contact members occurs rapidly and inherently upon a slight backward move ment of the controller without requiring the use of a pneumatic engine or other power actuated device.

'Thecontrollen shaft is maintained in the shifting pos tion during the further back-' ward'movement of the controller by reason 7 0 f thesmaller diameter ofthe cam surface 202 until a region'marked 50, wh1chcorre} j spondsto the .off position of the con- *troller, is reached. At thecentralpointof the'region 5c, the cam surface 202 and the groove 210 are substantially'tangent, so that the expansive action of the 'spring 220 forces the roller-21a into the illustrated normal or initial position; while the releaseofthe roller 21% from engagement with the left-hand face of the intermediate cam portion 203 permits the main spring 227 to retract the controller shaft its initial or contact-permitting position.

Reference may now be had to Fig. 17, which semidiagrammatically illustrates a modified and somewhat simplified complete system corresponding to Fig. 1.

The system shown comprises a fluid-pressure-operated controller-actuating mechanism 231; a manually-actuated pneumatic control valve 232; an automatic operating valve 233; an electro-pneumatic limit valve 234; an electro-pneumatic overload trip valve 235; a fluid-pressure-operated main reverser 236; a manually-operated master reve 'ser va vs 237; and a plurality of train pipes 238.

It will be noted that, in the present system, only a single automatic operating valve and a single limit valve are necessary in lieu of the two valves of each kind that are required in the system shown in Fig. 1 and, further, that the number of train pipes has been decreased.

The controller-actuating mechanism 231 is similar to the previously-described actuating mechanism 1, comprising a rack member 240 which meshes with the pinion 9 on the controller shaft 10 and the opposite ends of which rack member constitute pistons 241 and 242 that travel within suitable operating cylinders 24:3 and 24 1, respectively. A combined inlet and outlet pipe 245 serves to connect the outer end of the cylinder 231 to the electro-pneumatic overload trip valve 235, while the outer end oi the other operating cylinder is provided with two pipes 01"conduits 2&6 and 247 which respectively communicate with opposite ends of the automatic 0 crating valve 233.

The manual control valve 232 is shown as comprising a movable plate or disk 2% which is rigidly mounted upon'a centrallylocated shaft 2&9 and which is provined with a plurality of outlet ports 250 and 251 that are operative when the valve occupies the illustrated normalor oil position, as subsequently more fully set forth. The plate 248 is further provided with a plurality oi recesses or depressions 252 and in its under surface, for the purpose oi effecting communication between pairs of pipes or conduits 254 and 255, and 256 and 25?, respectively. The pipe 254: leads into the master reverser valve 237; the pipe 255 is supply pipe communicating directly with the reservoir or other source of fluid pressure; the pipe 256 is connected to the limit valv 234i: and the pipe 257 communicates with the overload trip valve 235 and with the pneumatic reverser 236, as hereinafter traced in detail.

In the present instance, the manual control valve 232 may be provided with an actuating device similar to that used in the familiar engineers valve for air-braking systems or, if desired, the actuating mechanism shown in Fig. 2 and Fig. 3 maybe associated with the movable plate 248.

The automatic operating-valve 233 comprises a duplex tubular iii-casing member 260, within which is centrally positioned two alined valve pins or stems 261 and 261* that are respectively provided with an upper plug valve 263 and a lower plug valve An intermediately located piston 262 is rigidly mounted upon the stem 261 and a spring 266 serves to resiliently connect the two valve rods. A plurality of further coil springs 265 and 267 are provided to respectively bear downwardly against the upper plug valve 263 and the lower plug valve 26%, whereby the various movable elements are normally biased to the illustrated posi tions.

Qutlet ports 268 and 269 are provided for the upper and the lower portions, respectively, or" the automatic operating valve, while pipes or conduits 2 16 and 2'70, communicating respectively with the operating cylind r 2%- ano the reservoir, are connected to the upper valve portion; and pipes 24;? and 271, communicating, respectively, with the operating cylinder 2% and the limit valve 234;, lead into the lower valve portion.

The electro-pneumatic limit valve 234 is of the same typ the previously-described valve comprisng. in general, an incasing shell 280 and a plug valve 281, the stem 282 of which is associated with an actuating coil that is energized by the motor current similarly. to the apparatus shown in Fig. 1. A lower outlet port 283 for the valve is provided, and an inlet pipe 284 communicates through train pipe 285 to the pipe 256.

The electro-pneumatic overload trip valve 235 is simplified in form from the valve 5 of Fig. 1 and comprises essentially an incasing member 288 and a plug valve 289, the stem 290 of which is adapted to be upwardly actuated when the current traversing an energizing coil (not shown) that is connected in the motor circuit, is excited above a predetermined degree. The valve 235 is provided wi h a lower outlet portand an upper inlet pipe 292 which communicates with the pipe 257.

The main reverser 236 is of type that is familiar in general comprising a plurality of pistons 295 and 296 which respectively travel within suitable operating cylin ders 29? and 298 and are rigidly connect-2t by a stem or rod 299 having an int rmerliate pivotal joint 300 with an oscillatable link or arm 301 which is rigidly secured to the movable member of a two-way valve 302 having an internal passage 303 that communicates in the position shown, with pipes 304 and 305, respectively leading to the 7 the valve is indicated at .317.

cylinder 297 and to the pipe 257. A further pipe 306 which is closed in the illustrated position of the two-Way valve communicates through pipe 310 to train pipe 311 and also 7 to a pipe 312 which is connected to the master reverser valve 237.

a A further pipe 307 effects communication from the cylinder 297 through train pipe 308 to pipe 309 which leads into the master reverser valve 237.

The manually-operated reverser valve 237 comprises a centrally-located operating shaft 314, upon which is rigi'dlyrmounted a 3, for example, to prevent undesirable rela- .tive movement of the two valves, corresponding to the customary interlocking'between electrical master controllers and master reversers. V

Assuming that the main reverser 236 occupies the illustrated forward position and that the master reverser valve 237 isjac tuated to its reverse position, upon actuation' of the manual control valve'232' to its first OPBHLJGIVG' position, fluid pressure is conveyed from the reservoir throngh pipe 7 255, recess 252 in the under srde'of the plate 248 of the manual control valve pipe 254, which registers with the outlet port 25.0 only in the ofl'i position of the control valve, thence through internal passage 31 6 of the master reverser valve 237, and pipes;

312 and 310 to the operating cylinder 2 98.

In this way, fluid pressure is admitted to the reverse cylinder of the main reverser, and the two-way valve 302 is actuated into such a position that pipes 305 and 306 are placed in communication through the internal passage 303 of the valve, whereby operation of the controllei actuating mechanism 231 is permitted, as subsequently oescribed.

A a corresponding operation takes place whenever the main reverser 236 occuplies its reversed position and the master reverser valve 237 is moved to its forward position, while'the manual control valve 232; occupies its first operative position.

When the various pieces of control apparatus occupy the illustrated positions, the operating cylinder 243 of the controllere actuating mechanism 231 is connected through pipe 245, internal passage of the electro-pneumatic overload trip valve 235, pipes'292 and 305, internal passage the'two-way valve 302 pipes 304 and 307, train pipe 308, pipe 309,'internal passagev 316 of the master reverser valve 237 and pipe 254 to outlet port 250, whereby the operating'oylinder'243 isv normally placed in communication with the atmosphere. G11 the other hand, the operating cylinder 244 communicates through pipe 246, internal,

passage 'ofthe automatic operating valve 233 above the lru 263 and )1 )e 270 to the c l l r H reservoir,wherebyfluid pressure is normally admitted to the cylinder 244 to bias the controller-actuating mechanism to the illustrated position. 7

Assuming that the various parts of the control apparatus occupy the illustrated positions, the complete operation of the sys tem may be set'forth as follows: Upon actuation of the manual control valve 232 to its first operative position, fluid pressure is conducted from the reservoir through pipe 255, recessi252 and pipe 254, internal passage 316 of the master reverser valve, pipe 309, train pipe 308, pipes 307 and 304 (no movement of the main reverser occurring,

since it already :occupies its forward posi 1 tion), and thence through internal passage 303 of the two-way valve 302, p1pes 305 and 292, an internal passage of the electro-pncnmatlc overload tr1pvalve 235, in its illustrated lower position and pipe 245 to the l 4' 1. 11 operatlng cylinder 243 Or the controlleractuating mechanism 231.

this time by reason of the balanced fluidprelssure conditions in the two cylinders 233 and; 234. Fluid pressure is also conveyed through a branch pipe 257 from the pipe plate 248 of the manual control valve, pipe 256, train-pipe 285, pipe 284, internal pas- V sage of the electro-pneumatic limit valve 234 in its illustrated lower position and. pipe 271 to the automatic operating valve 233.

The influx of fluidv pressure to the valve eflects an elevation of the. piston v2'62 to correspondingly raise the plug valves'263 and 264 to their upper positions. In this way, fluid pressure is exhausted from the operating cylinder 244 through pipe24; and iii-,

However, no movement thereof occurs 305'to. the recess 253 in the under side o1 the ternal passage of the automatic operating valve belowthe plug valve 264 and thence to the atmosphere through outlet port 269. Such gradual release of fluid pressure from the cylinder 244 permits a movement of the pistons 241 and 242 toward ther'ight, since high fluid pressure is present in the other operating cylinder 243. Such piston movement' eflects the desired rotative actuation of the controller shaft 10 in the previouslydescribed manner, V

The movement of the controller shaft is interrupted whenever the electro-pneumatic limit valve 234 is raised to its upper position, whereby fluid pressure is shut ofi from the inlet pipe 271 to the automatic operating valve 233, thus permitting the spring 267 toreturn the plug valves 263 and 264: to the illustrated lower positions. In this way, fluid pressure is re-ad nitted from the reservoir through the automatic operating valve 233 to the operating cylinder 2 14 whereby a positive and reliable stoppage of the controller-actuating mechanism is effected. Automatic step-by-step operation of the controller shaft is thus produced, in accordance with the movements of the electropneumatic limit valve 23 1.

Upon the occurrence of an overload curr nt which effects the actuation of the electro-pneumatic overload trip valve 235 to its upper position, the fiuid pressure in the operating cylinder 243 is immediately 6X hausted through the pipe and internal passage of the trip valve beneath the plug and thence through the outlet port 291. Thus, movement 01 the controllenactuating mechanism toward the illustrated oft position is produced as long as the overload conditions are maintained, since the electropneumatic limit valve 23%- also occupies its upper position at this time, thereby permitting the admission 01": fluid pressure to the operating cylinder 24%.

To prevent the controller-actuating mechanism 231 from stopping in a position intermediate the desired controller notches, an auxiliary cam mechanism may be employed to interconnect the automatic operating valve 233 with the controller shaft 10. Such a mechanism may comprise a cam plate or disk 275 which is provided with a plurality of lateral recesses or depressions 276,, for the purpose of receiving the lower end of the valve spindle 261 in the respective notches or positions of the controller shaft 10 that correspond to the desired electrical connections. The cam plate 275 is mounted unon stem or rod which constitutes .xtension of the controller shaft 10. Conse quently, when the electro-pneumatic limit valve 23% is actuated to out on fluid pressure 'rom the lower portion o1 the automatic operating valve 233 and the shy tend to permit the movement thereof to the illusraed position, such movement is, in reality, 3evented by the cam plate 275 until the next recess 276 is reached. In this way, the

tr vl of th rontroller from one notch to the next notch is insured and false connections or burning or electrical contact memhers is precluded. 4 p

The simplified form of automatic operating valve that is shown in Fig. 18 may be employed in lieu of the illustrated valve 233, whereby tl e pipe 2%? is dispensed with. The ave in question comprises a shell or incasing member 325 with the upper and lower ends of which the pipes 270 and 211 respectively comn'mnicate. A movable spindle 32 is provided at opposite ends with a pin valve and piston 328. ii coil sprin 325), acting betwee a lower tired valve-Se 33F and the piston 32S, serves to bias the movable valve parts to the illustrated position, whereby communication is normally established from the supply pipe 270 through an internal passage 331 to the pipe which leads into the operating cylinder 2&4 of the controller-actuating mechanism 231. An intermediately located outlet port 332 isnormally shut oil by the plug valve 327 from communication with the pipe 24:6.

In view of the similarity of the automatic operating valve just described to the valve 233, only brief description or" its operation will be necessary. When fluid pressure is admitted through the pipe 221 from the manual control valve and the electropneumatic limit valve 234, the piston 328 is forced upwardly to seat the plug valve 327 in its upper position, whereby communica tion between pipes 270 and 2&6 is interrupted to effect movement of the controlleractuating mechanism 231 in manner previously described, by permitting the release of tluid pressure from the operating cylinder 24%, through the pipe 246 and beneath the plug valve 327 to the outlet 332. Upon the lifting oi the electro-pneumatic limit valve 23%, the supply of fluid pressure to the pipe 271 is cut oil, thereby permitting the coil spring to return the automatic operating to the illustrated normal position and i the movement of the controller-actuti g mechanism.

8 me form of controller-shifting appantus, such as that illustrated in Fig. 6 to rig. 8, inclusive, or Fig. 12 to Fig. 16, inlusive, is preferably associated with the controller shai't 10 of Fig. 1?, for the previudy-described pu pose of op ning all conact members pen a baclrwa imoveinent of he controller prevent burning and undue 2 the contact members.

vn operating economy, the pipes or ling directly from the 'servoir to the control valve may be or relatively large diameter, iile the distributing pipes that commun-Jte with the various pieces of control apparatus may he of smaller diai'neter. In this way, a relatively small volume oi operating fluid is required. and the increased pressure thereof in smaller pipes results in a quick and positive action of the automatic operating valve.

It will be appreciated that my nil-DHGH- ma ic control systems may readily be adapted for use with ei her auton'iatic nonautomatic acceleration of the overned motors. Furthermore, the electrical circuits will not be initially closed unless the fluidpressure'is sufficient loo-adequately control thevehicle, thus providing a desirable safety feature.

I do not Wish to be restricted to the specific structural details or arrangement of parts herein set forth, as various other modifications thereof may be effected Without de-' partin from the spirit and scope of my invention. I desire, therefore, that only such 10 limitations shal beimposed as are indicated in the appended claims.

I claim as my invention 1. A control system comprising a multiposition circuit-governing -member, fluid pressure operated means for actuating said member in the one or the other direction,

' valve means normally biased to a closed position but operative during actuation of said member to permit the release-offluid pressure from oneside of said actuating means, and means dependent upon predetermined conditions for automatically restoring the normal biasing effect in said valve means.

2. A control system for dynamo-electric 7 machinescomprising a rotatable machinecurrent conditions for automatically restoring thenormal biasing effect in said duplex valve means. r V

3. A control system' for dynamo-electric machines comprising a rotatable machinecircuit governing member, a cylinderandpiston apparatus for actuating said member in the one or the. other direction, duplex valve means normally biased to a closed position but having an open passage during actuation of said member to permit the release of fluid pressure from one side of said actuating means, manual control means for normally admitting fluid pressureto that side, means for actuating said control means to admit fluid pressure to the other side of said actuating means to efiect movement thereof, and further valve means dependent upon predetermined machine-current conditions for automatically restoring the normal "biasing effect in said duplex valve means to arrest'said movement.

4L. A control system comprising a multiposition circuit-governing member, fluidpressure-operated means for actuating said member in the one or the other direction,

7 valve means normally biased to a closed position but operative during actuation of said member to permit the release of fluid pressure from one side of said actuating means, means dependent upon predetermined condltions for automatlcally restoring the-normal biasing effect in said valve 7 means, and pneumatic means dependent upon other conditions'for automatically efrectmg.themeturn'movement of saidcircuit- V governing. member.

5. A control system for dynamo-electric machines comprising a rotatable machme circuit-governing member, a' cylinder-andplston apparatus for actuating. said mem her in the one-or. the other directiomduplex valve means normally biased to, a:closed position but having anopen-passage during actuation of said member to permit the: re

lease of fluid pressure from one side of said' actuating 'means, further valve means dependent upon predetermined. machine-current conditions for automatically restoring the normal biasing effect in said duplex valve means, and pneumatic means dependent upon higher-current conditions for automatically effectinga reversal of fluidpressure conditions in said apparatus and a,

return movement thereof.

(3. A control system for dynamo-electric machines comprising a rotatable machine-- circuit-governing member, a cylinder-andpiston apparatus forv actuating said member in the one or the other direction, duplex valve means normally biased to a closedposition but having an open passage during actuation of said member. to permit the release of fluid pressure from one side of said actuation means, further valve. means dependent upon predetermined machine-cur- 7 rent conditions for automaticallyrestoring the normal biasmg' effect in sald duplex valve means,'means for longitudinally shifting said circuit-governing member to interrupt the machine circuits, and pneumatic means dependent upon relatively high-current conditions for automatically effecting the operation of said longitudinal shifting means.

*T A control system for dynamo-electric machines comprising a rotatable machinecircuit-governing member, a cylinder-andpiston apparatus for actuatmg said memher in the one or the other direction, duplex valve means normally biased to a closed po-' sition but havingqan open passage during actuation of said member to permit therea lease offiuid pressure from one side of saidactuating means, further valve. means:- dependent upon predetermined machine-current conditions for automatically restoring the normal biasing effect in said duplex valve means, means for longitudinally shifting said circuit governing member to interrupt the machine circuits, and pneumatic means dependent'upon relatively high-cue rent conditions for automatically eifecting 

